Question

I created a protocol and a class to use the protocol.

JSTest.h file =

@protocol JSTestDelegate

@end

@interface JSTest : NSObject {

    id<JSTestDelegate> delegate;
}

@property (nonatomic, retain) id<JSTestDelegate> delegate;

- (id)initWithDelegate:(id<JSTestDelegate>)del;

@end

JSTest.m file =

#import "JSTest.h"


@implementation JSTest

@synthesize delegate;

- (id)initWithDelegate:(id<JSTestDelegate>)del {

    self = [super init];

    if(self) {

        self.delegate = del;
    }

    return self;
}

- (void)dealloc {

    [delegate release];
    [super dealloc];
}

My issue is – in the dealloc method, the

[delegate release]

gives me a warning

-release not found in protocol(s)

I am unable to determine the reason. My code should not fail because the delegate will always be a subclass of NSObject. However, I have had bad experiences with warnings that I ignored without understanding the reason for the warning to show up.

Answer 1

There’s a NSObject protocol that you can inherit from (reference here). That protocol contains the basic methods of any NSObject.

By making your own protocol comply with it, you’ll be able to call -release without getting any compiler warning.

Sample code:

@protocol JSTestDelegate<NSObject>

@end